CUKURCA, Turkey - A Turkish helicopter crashed in Iraq, and eight soldiers were killed during a cross-border ground operation against Kurdish rebels, who planted booby traps on the bodies of their slain comrades, Turkey's military said yesterday.

The guerrillas said they shot down a Turkish military helicopter near the Iraqi border. Turkey's military said technicians were inspecting the wreck to determine why it crashed. It was not clear whether any of the reported troop casualties were from the crash. Since the start of the incursion Thursday, 15 Turkish soldiers have died, the military said on its website.

Thirty-three rebels were killed in the fighting yesterday, bringing the rebel death toll since Thursday to 112, according to the armed forces.

The incursion is the first confirmed Turkish military ground operation in Iraq since the US-led invasion that toppled Saddam Hussein in 2003.

The rebels of the Kurdistan Workers' Party, or PKK, are fighting for autonomy in predominantly Kurdish southeastern Turkey and have carried out attacks on Turkish targets from bases in the semiautonomous Kurdish region of northern Iraq. The conflict started in 1984 and has killed as many as 40,000.

Turkey has assured concerned allies that the operation would be limited to attacks on rebels. The United States and European Union consider the PKK a terrorist group.

"It is only an operation geared to cleansing the terrorist camps," Turkey's prime minister, Recep Tayyip Erdogan, said yesterday in an address to the youth branch of his ruling party. "Our Iraqi brothers, friends, and civilians should know that they will never be targeted by the armed forces."

US Defense Secretary Robert Gates said yesterday while visiting Australia that it would take a broader approach to erode PKK support in northern Iraq.

"After a certain point people become inured to military attacks," he said, "and if you don't blend them with these kinds of nonmilitary initiatives, then at a certain point the military efforts become less and less effective."

Massoud Barzani, head of the regional Kurdish administration in northern Iraq, warned that Turkey would face large-scale resistance if it targeted civilians in its incursion.

The Iraqi government said Saturday that fewer than 1,000 Turkish soldiers had crossed the frontier. Turkish media reports put the number in the thousands.

"We demand that the Turkish government withdraw its forces immediately from the Iraqi territory and rely on negotiations to solve this conflict," the cleric's political committee said in a statement.

Iran, which is fighting an Iraq-based group of Kurdish militants with PKK links, said it would maintain security measures on its border with northern Iraq.

The Turkish military said clashes with the rebels were taking place in four areas of northern Iraq but did not specify any of them.

"Terrorist hide-outs have been effectively destroyed by warplanes, helicopter gunships, and artillery," the military said.

It said advancing troops were destroying rebel shelters, logistic centers, and ammunition. Retreating rebels were trying to gain time by setting up booby traps under the corpses of dead comrades or planting mines on escape routes, the military said.

The bodies of five of the 33 rebels killed yesterday had booby traps under them, the statement said.

Late yesterday, several military helicopters took off from a base in the hilltop town of Cukurca, flying with their lights off. Earlier, Turkish F-16 jets flew into northern Iraq. Armored personnel carriers transported troops, and four long-range guns were positioned at the Cukurca base.